1. Technical Field
The present invention generally relates to a circularly polarized Global Positioning System (GPS) antenna using parasitic lines and, more particularly, to a circularly polarized GPS antenna using parasitic lines, in which circular polarization is implemented to improve the efficiency of the reception of satellite signals by an antenna.
2. Description of the Related Art
Microstrip patch antennas, which are chiefly used as antennas for satellite communication, are implemented as planar antennas. Such a microstrip patch antenna is one of the most widely used kinds of antenna in Radio Frequency (RF) fields because the lightweight structure, integration, and arrangement of antennas are easily implemented, and the manufacturing process thereof is simplified to improve economic efficiency. In particular, in various applications for providing information about the time and location of moving objects, such as mobile devices, vehicles, vessels, and airplanes, a GPS antenna plays an important role.
However, such a GPS receives satellite signals transmitted from a location at an altitude of 20,000 km from the earth, and power is transferred while passing through the ionosphere. Accordingly, in order to minimize power loss in the ionosphere, an antenna having circular polarization characteristics is required.
In this way, in order to derive circular polarization characteristics, an antenna is generally designed such that the corners of a microstrip patch antenna are rasped off or slots are formed, thus enabling the direction of current induced in a radiating patch to be rotated depending on the phase. However, conventional technologies exhibit narrowband circular polarization characteristics, and the performance of such antennas is sensitive to the sizes of rasped-off corners and slots, thus requiring additional performance tuning.
In relation to this technology, Korean Patent Application Publication No. 10-2010-0045200 discloses a GPS ceramic patch antenna. Korean Patent Application Publication No. 10-2010-0045200 also discloses technology in which the corners of a radiating patch are rasped off so as to implement circular polarization, and slots having various shapes are additionally provided, but a problem arises in that the complexity of the design is increased due to a slot addition structure and the like.